1. Field of the Invention
The present invention relates to a photopolymerizable composition and a recording material, more particularly to a photopolymerizable composition and a recording material, which are preferably usable in a wide range of fields such as a cyanine-based organic dyes, inks, color filters, holograms, proofs, sealing agents, adhesives, planographic printing, resin relief printing plates, photoresists and the like.
2. Description of the Related Art
The photopolymerizable composition basically contains a photopolymerization initiator and an addition-polymerizable compound (hereinafter referred to as polyfunctional monomer) having two or more ethylenic unsaturated bonds in a molecule. The photopolymerizable composition is cured by light radiation, has change of viscosity, and becomes insoluble in solvents. To utilize these characteristics, the composition is widely used for photography, printing, metal surface processing, ink and the like. The functions and the application examples of the photopolymerizable composition are described in many published printed matter.
For example, detailed descriptions are given in J. Kosar, Light Sensitive Systems (New York: J. Wiley and Sons, 1965) pp. 158-193; and K. I. Jacobson and R. E. Jacobson, Imaging Systems (New York: J. Wiley and Sons 1976) pp. 181-222; and the like.
Further, as an image forming method using a photopolymerizable composition, an image forming system using a photosensitive microcapsule encapsulating a photopolymerizable composition has been proposed recently. For example, Japanese Patent Application Laid-Open (JP-A) Nos. 57-124343, 57-179836, and 57-197538 disclose color image formation methods comprising steps of laminating a color formation sheet, which is coated with a microcapsule that enencapsulates a dye and a photopolymerizable composition that contains a vinyl compound and a photopolymerization initiator, and an image receiving sheet after exposure and applying pressure to the whole body.
Further, JP-A Nos. 3-87827 and 4-211252 describe photosensitive and heat-sensitive color recording material containing two components and disclose recording materials, in which one of two components is enencapsulated in a microcapsule and the other component is either a curable compound of a photo curable composition or is included together with a photo curable composition outside of the microcapsule. Further, in the latter recording material, a photosensitive and heat-sensitive recording material is exemplified which has a layer containing a microcapsule enencapsulating an electron-donating colorless dye and, the outside of the microcapsule, a photo curable composition containing an electron-accepting compound, a polymerizable vinyl monomer, and a photopolymerization initiator.
As described above, the recording material utilizing the photopolymerizable composition is capable of image recording in a completely dry system without using a developing solution or the like and is thus remarkably preferable with regard to the environments in that no waste is discharged.
In the case of an image recording, which uses a photosensitive recording material, it is advantageous if the photosensitive recording material can use not only UV rays and short wave visible light rays but also economical IR laser and blue to red color rays. However, when the recording material uses the photopolymerizable composition, the recording material may be sensitive to UV rays but insensitive to visible light rays to IR rays or even if sensitive to them, the sensitivity may not be sufficient in many cases and consequently, the formed images may become unclear or the contrast between an image area and a non-image area may be low in and higher sensitivity is desired.
On the other hand, inventors of the invention have proposed a compound having a thiol group for a polymerization auxiliary agent as a photopolymerizable composition usable for the recording material mentioned above and have solved the problems of the sensitivity improvement and the sensitivity to a light source for visible light rays or higher (JP-A No. 64-13144). However, if the photopolymerizable composition is applied to a recording material, for example, in the case when a vinyl sulfone type film curing agent is used in a gelatin binder system, the foregoing polymerization auxiliary agent sometimes reacts with the film curing agent to result in deterioration of storage stability and alteration of the photosensitivity based on the humidity, thus further improvements still remain to be done.